Conventional travel planning systems (TPSes) are used to produce itineraries and prices by selecting suitable travel units from databases containing geographic, scheduling and pricing information. In the airline industry, for example, fundamental travel units include “flights” (sequences of regularly scheduled takeoffs and landings assigned a common identifier) and “fares” (prices published by airlines for travel between two points). The term “itinerary” refers to a sequence of flights on particular dates and the term “pricing solution” refers to a combination of fares and itineraries.
In conventional travel planning such as for air travel scheduling, flight pricing and low-fare-searching, travel queries are posed by users from travel agent systems, airline reservation agent systems, travel web sites, and airline-specific web sites. Low-fare-search (LFS) queries typically include origin and destination information, time constraints, and may include additional information such as passenger profile and travel preferences. TPSes respond to these LFS queries and typically return a list of possible travel options of a flight combination with price information.
TPSes expend considerable computational resources responding to LFS queries. It is not uncommon for a TPS to spend more than 30 seconds responding to an LFS query, even for a relatively straightforward round-trip query leaving and returning from specific airports on specific dates. This delay is undesirable for the user of the system, as it reduces interactivity.